Telescoping cannula

ABSTRACT

An apparatus may serve as a surgical portal for the reception of surgical instruments for use in laparoscopic or similar surgery. The apparatus may include inner and outer tubular elongate members adapted for a longitudinal translation relative to one another to effect a length adjustment of the apparatus. An interface between the two elongate members includes a helical thread providing a mechanism for the translation of the elongate members, and indentations in one of the members provides a locking mechanism for affixing the length.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 12/400,912, filed Mar. 10, 2009 now U.S. Pat. No. 7,828,775,which claims priority to U.S. Provisional Patent Application Ser. No.61/044,183, filed on Apr. 11, 2008, the entire content of each of theseapplications being incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to an apparatus for permittingthe introduction of a surgical instrument into a patient's body cavityin a laparoscopic or similar surgery. In particular, the disclosurerelates to a telescoping cannula assembly configured for longitudinalextension and retraction to effect a length adjustment.

2. Background of Related Art

A relatively small incision is required for minimally invasive surgicalprocedures such as laparoscopic, arthroscopic, and endoscopic proceduresas compared with conventional open procedures. Small incisions arepreferred because they are inherently less traumatic to the body tissueand subject internal organs to a minimum of exposure to contaminants inthe outside atmosphere. Thus, small incisions enable shorter hospitalstays and faster recoveries with less pain and scarring than is commonwith the larger incisions required for conventional surgery.

Minimally invasive surgery is possible due in part to the availabilityof instruments designed specifically for this purpose. A cannula, forexample, is an elongated tube that may be inserted through the smallincision made in a body cavity wall of a patient to provide a workingconduit between an internal body cavity adjacent an operative site andthe environment exterior to the patient. The body cavity is ofteninflated with an insufflation gas such as carbon dioxide to separate thebody cavity wall from vital organs and to provide some space where adistal end of the cannula can safely protrude into the patient below thebody cavity wall.

The length of a cannula is generally selected to span a range ofanatomies and consequently a portion of the cannula assembly whichremains on the outside of the patient may extend above the body cavitywall to a greater extent than otherwise desired. The cannula assemblymay need to extend into deeper regions of the body cavity, e.g., theabdominal cavity, to access remote underlying organs therein.Furthermore, because several instruments of various lengths might berequired for a surgical procedure, an instrument may protrude above thecannula assembly to a greater extent than otherwise desired.Accordingly, a need exists for a cannula assembly which facilitates theintroduction of surgical instruments to a surgical site, while allowinga longitudinal retraction or extension to effect an adjustment inlength.

SUMMARY

The present disclosure describes a surgical portal apparatus whichpermits a length adjustment to accommodate a range of body cavity wallthicknesses. The apparatus comprises a tubular elongate inner memberadapted and sized appropriately for the introduction of a surgicalinstrument. The elongate inner member has a proximal end, a distal endand a length therebetween, with a portion of the length radiallysurrounded by a tubular elongate outer member. A length adjustmentstructure provides an adjustment interface between the elongate innermember and the elongate outer member. The length adjustment structureincludes a generally helical thread on at least one of the elongatemembers and feature on the other for engaging the thread. A lengthfixation structure includes inter-engaging components for selectivelyand non-permanently securing a longitudinal position of the elongateinner member within the elongate outer member.

The inter-engaging components may include a series of indentationsarranged in a generally helical pattern corresponding to the generallyhelical thread. The series of indentations may be disposed on aninterior surface of the generally helical thread. The surgical portalapparatus may include a housing at or near the proximal end containing aseal apparatus capable of sealing the apparatus before, during and afterthe introduction of a surgical instrument. The housing may include aconnection for introducing an insufflation gas into the body cavity. Theelongate outer member may be positioned distally of the elongate innermember.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and, together with the detailed description of theembodiments given below, serve to explain the principles of thedisclosure.

FIG. 1 is a side view of a surgical portal apparatus in accordance withthe present disclosure inserted through a body cavity wall;

FIG. 2 is a partial cross-sectional view of the telescoping cannulaassembly of FIG. 1;

FIG. 3A is an enlarged view of the area of detail identified in FIG. 2;

FIG. 3B is a view similar to view 3A depicting an alternate lengthfixation structure; and

FIG. 3C is a view similar to view 3A depicting another alternate lengthfixation structure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The attached figures illustrate exemplary embodiments of the presentdisclosure and are referenced to describe the embodiments depictedtherein. Hereinafter, the disclosure will be described in detail byexplaining the figures wherein like reference numerals represent likeparts throughout the several views.

The present disclosure contemplates the introduction into a person'sbody of all types of surgical instruments including clip appliers,graspers, dissectors, retractors, staplers, laser fibers, photographicdevices, endoscopes and laparoscopes, tubes, and the like. All suchobjects are referred to herein generally as “instruments.” In thedrawings and in the description that follows, the term “proximal,” as istraditional, will refer to the direction toward the operator or arelative position on the surgical device or instrument that is closer tothe operator, while the term “distal” will refer to the direction awayfrom the operator or relative position of the instrument that is furtherfrom the operator.

Referring initially to FIG. 1, a surgical portal apparatus is generallydepicted as telescoping cannula assembly 10. Telescoping cannulaassembly 10 includes an elongate outer member 14, an elongate innermember 18 and a housing 22. Elongate outer member 14 is positionedthrough the skin 26 and within a layer of body tissue 28. Skin 26 andbody tissue 28 together define a body cavity wall 30 with a thickness“t.” A distal end 34 of the elongate outer member 14 protrudes into aninterior body cavity of a patient, and housing 22 remains in an exteriorenvironment. A proximal end 38 of elongate inner member 18 may berigidly coupled to housing 22 such that there is no relative motiontherebetween, and a distal end 40 (FIG. 2) of inner member 18 istelescopically arranged within elongate outer member 14. Using a lengthadjustment structure as described in greater detail below, the overalllength “L” of telescoping cannula assembly 10 may be adjusted byretracting or extending elongate inner member 18, for example toaccommodate a variance in the thickness “t” of body cavity wall 30.

Referring now to FIG. 2, telescoping cannula assembly 10 is depicted inpartial cross section. Housing 22 includes an insufflation gas valve 44and internal seal system 46, which may be capable of permitting thepassage of an instrument while preventing insufflation gasses fromescaping through a proximal end of telescoping cannula assembly 10before, during and after introduction of the instrument. Internal sealsystem 46 may take any form including the form described in U.S. Pat.No. 5,603,702 to Smith et al., filed Aug. 8, 1994, the entire contentsof which are hereby incorporated by reference.

Elongate inner member 18 includes a longitudinal bore 50 defining apassageway adapted for the introduction of an instrument. The distal end40 and a substantial portion of elongate inner member 18 are radiallysurrounded by elongate outer member 14. A length adjustment structuredefines the degree to which elongate inner member 18 is nested withinelongate outer member 14 and therefore, the overall length L oftelescoping cannula assembly 10.

The length adjustment structure may include a female thread 52 (shown inphantom) disposed on an outer surface 58 of elongate inner member 18. Acorresponding male protrusion 60 or rib is disposed on an interiorsurface 62 of elongate outer member 14 and extends into thread 52. Maleprotrusion 60 may take the form of a full male thread. Alternatively,male protrusion 60 may comprise one or more narrow tabs appropriatelypositioned to guide the relative motion of elongate outer member 14along thread 52. As seen best in FIG. 3A, thread 52 includes severalinterior surfaces 64 for engaging male protrusion 60. Thread 52 mayexhibit a course pitch allowing for large adjustments to be made quicklyrequiring only a few rotations of either the inner or outer elongatemember 18, 14. The overall length of cannula assembly may be adjusted bycorresponding rotational movement of inner member 18 and outer member14.

As seen in FIG. 3B, a length fixation structure may comprise a series ofindentations 66 on the exterior surface 58 of elongate inner member 18.Indentations 66 may be discrete, incrementally spaced notches orserrations arranged along the length of elongate inner member 18. Malerib 68 may extend into an indentation 66 to non-permanently arrest therelative motion of elongate inner and outer members 14, 18. Whensufficient force is applied to either the elongate inner or outer member14, 18 in an axial direction, male rib 68 may be temporarily displacedto move over ridges 70 between indentations 66. In this way, male rib 68can act as a pawl engaging a ratchet formed from the series ofindentations 66 and ridges 70 to non-permanently fix the overall length“L” of cannula assembly 10. Male rib 68 may be formed from a flexiblematerial, ball plunger, or other suitable arrangement. Indentations 66and male rib 68 may encircle elongate inner member or any part thereof.

Referring now to FIG. 3C, a length adjustment interface is describedthat incorporates a length adjustment structure and a length fixationstructure. A helical thread 72 wraps around elongate inner member 18.Helical thread 72 is equipped with a series of internal spaced ridges ordetents 74 and indentations (not visible) between ridges 74 arrangedalong a helical path corresponding to an inner surface 78 of thread 72.Male protrusion 80 is equipped with male rib or pawl 88 configured tointerface with the indentations between ridges 74 in, e.g., a pawldetent arrangement or in the manner described in connection with theembodiment of FIG. 3B. Male protrusion 80 may alternatively be adaptedto engage the indentations between ridges 74 directly.

The positioning of the indentations may take various forms. For example,the indentations may be positioned in a helical path on the outsidesurface 58 of elongate inner member 18 rather than on an inside surface78 of thread 72. In this case a male rib 88 on the inside surface 62 ofelongate outer member may engage the indentations to secure the relativepositions of elongate members 14, 18. Also, rather than resemblingclosely spaced serrations, the indentations may comprise a limitednumber of strategically placed detents to accommodate the use ofstandard sized instruments or to accommodate the most typical tissuethicknesses.

In use, the overall length “L” of telescoping cannula 10 may be adjustedby rotating elongate inner member 18 along thread 72 until elongateinner member 18 reaches a satisfactory longitudinal position withinelongate outer member 14. The engagement of male rib 88 with anindentation may provide a tactile queue that such a position has beenachieved. The engagement of male rib 88 is sufficiently robust toprevent any unintended longitudinal migration of elongate inner member18 under the weight of housing 22 and other forces associated withintroducing and manipulating a surgical instrument.

In drawing figures and the corresponding descriptions above, the malefeatures of the adjustment interface have been associated with theelongate outer member 14 and the female components have been associatedwith the elongate inner member 18. However, this convention made forclarity may be reversed and these features may be associated with eitherelongate member 18, 14. Also, the elongate inner member has beendescribed as fixedly attached to the housing 22 and the elongate outermember movable relative to the housing and elongate inner member. Thisconvention may also be reversed such that the elongate outer member isfixedly attached to the housing and the elongate inner member is movablewithin the elongate outer member 14.

Although the foregoing disclosure has been described in some detail byway of illustration and example, for purposes of clarity orunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

1. A method of surgically accessing a body cavity through a body cavitywall, the method comprising the steps of: providing an adjustablesurgical portal apparatus including an inner member nested within anouter member, wherein the inner and outer members engage one another bya helical thread defined on at least one of the inner and outer members,and wherein a plurality of incrementally spaced indentations are definedalong the helical between a proximal end and a distal end of the helicalthread for releasably engaging a locking element defined on the other ofthe inner and outer members; rotating the inner and outer members withrespect to one another to displace the locking element from a first ofthe plurality of incrementally spaced indentions and subsequently engagethe locking element with a second of the indentations to adjust therelative longitudinal positioning of the inner and outer members suchthat the overall length of the portal apparatus is appropriate toaccommodate the thickness of the body cavity wall; and inserting adistal end of the surgical portal apparatus through the body cavity wallinto the body cavity.
 2. The method according to claim 1, wherein thestep or rotating the inner and outer members displaces the lockingelement from a plurality of the incrementally spaced indentations beforesubsequently engaging with the second of the indentations.
 3. The methodaccording to claim 1, wherein the step of rotating the inner and outermembers includes rotating the inner and outer members about alongitudinal axis defined by inner member.
 4. The method according toclaim 1, further comprising the step of introducing an instrumentthrough a passageway defined through the inner and outer members of thesurgical portal apparatus.
 5. The method according to claim 4, whereinthe step of introducing an instrument includes forming a seal betweenthe instrument and an internal seal system provided with the surgicalportal apparatus.
 6. A method of surgically accessing a body cavitythrough a body cavity wall having a thickness, the method comprising thesteps of: providing an adjustable surgical portal apparatus including aninner member nested within an outer member, wherein the inner and outermembers engage one another by a helical thread defined on at least oneof the inner and outer members, and wherein a plurality of incrementallyspaced indentations are defined along the helical thread between aproximal end and a distal end of the helical thread for releasablyengaging a locking element defined on the other of the inner and outermembers; determining an appropriate overall length of the portalapparatus to accommodate the thickness of the body cavity wall rotatingthe inner and outer members with respect to one another to displace thelocking element from a first of the plurality of incrementally spacedindentions; continuing to rotate the inner and outer members to engageand displace the locking element with an appropriate number of theindentations to adjust the overall length of the portal apparatus to theappropriate overall length of the portal apparatus; and inserting adistal end of the surgical portal apparatus through the body cavity wallinto the body cavity.